Predicting
the Weather: Forecasting

Backpackers on a long trip in a remote location often rely on their knowledge
of the clouds and wind to know what the weather will be like in a few
hours or the next day, but this method is not too reliable and cannot
be used to make predictions several days into the future.

The best forecasts take into account the weather events that are
happening over a broad region. Knowing where storms are now can
help forecasters
predict where storms will be tomorrow and the next day. Technology,
such as weather satellites and Doppler radar, helps the process
of looking
over a large area, as does the network of weather observations.

The chaotic nature of the atmosphere means that it will probably always
be impossible to predict the weather more than two weeks ahead; however,
new technologies combined with more traditional methods are allowing
forecasters to develop better and more complete forecasts. Read on
to learn more about some of these tools!

Doppler Radar
Unlike ordinary radar, which is able to report the location and strength
of precipitation, Doppler radar is additionally able to indicate
the wind direction, wind speed and boundaries between warm fronts
and cold
fronts. This is why Doppler radar has become such an indispensable
tool for weather forecasters.

Observation Tools
Satellites, dropsondes, weather stations, weather buoys, ships,
and airplanes are all sources of weather data. Weather stations
and buoys
record various
weather parameters at fixed locations. Ships and airplanes act
like moving weather stations, recording weather data at their current
position.
Also,
each day 1800 dropsondes collect weather information as they drop
through the sky after being launched from balloons or released
from airplanes.
Satellites, with their unique perspective on the weather, are important
sources of weather data as well. The data from all of these sources
are channeled into a supercomputer at a central location to make
weather predictions that take into account the current weather.

Computers
Numerical forecasting, or using mathematical calculations to predict
the weather, is not a job for the average calculator, or even
your average desktop computer! Supercomputers, which are capable
of doing more than
2 billion operations a second, are fed weather information
from satellites, weather stations, and other sources. To generate
weather
predictions,
they perform many calculations that take into account broad-scale
factors such as air pressure differences, solar
radiation, the
Earth’s
rotation, and the water cycle, as well as the current information.
This allows forecasters to generate more accurate forecasts based
on a comprehensive
regional perspective about the current weather, instead of
just observations at a single point. Thus, backpackers who sets out
into
the wilderness
knowing a weather forecast generated using computers and regional
data will have a good idea of the weather that they may encounter.